Electroresponsive device



March 8, 1938. v. E. VERRALL 2,110,686

' ELECTRORESFONSIVE DEVICE Filed March 24, 1936 2 Sheets-Sheet 1 Inventor: Victor E. \ler'r'al I,

Attorneg.

V. E. VERRALL ELECTRORESPONSIVE DEVICE March 8, 1938.

' Filed March 24, 1956 2 SheetsSheet 2 fig/0.

Fig.9

Inventor: Victor E. Var-Fal 7 ttor-neg.

7// r Mo F RE'ISSUED we? y I Patented Mar. 8, 1938 EIECTRORESPONSIVE DEVICE Victor E. Verrall, Upper Providence Township,

Delaware County, Pa., assignor to General Electric Company, a. corporation of New York Application March 24, 1936, Serial No. 70,580

19 Claims. (01. 171-452) My invention relates to improvements in elecstructlon and space, including switchboard space troresponsive devices and more particularly to requirements, are utilized to the best advantage, protective relays and, in general, the object of and which maybe readily modified, for example, my invention is to provide an electroresponsive to provide different fault responsive devices havdevice which is an improvement over devices ing a wide range of protective applications. A 5 heretofore known to the art. further object of my invention is to provide'an The rapid growth and the extensive interconimproved electroresponsive device unit, particunection of electric systems have raised proteclarly for multip un t, y which sures simtive requirements beyond the speed and sensi- D io y a d a y of assembly with que tivity possibilities .of induction disk relays. The reduction in manufacturing costs, whi equires 10 maximum torque of such relays is usually limited n ncl sin case, n whi h h a hi h rate of to a certain phase-angle between the circuits heat displacement. These and other objects of energizing the relay. That this phase angle or my invention will appear in more detail hereineyen a close approximation to it will exist during after. I

faulty conditions is uncertain, The torque 'My invention will be better understood from 15 tainable in such relays for a given input is limt wing description when considered in ited by inherent factors of design, such as high connection with e p y n wo sheets of air-gap reluctance and large flux leakage. The d w n and its scope W l be Po n d out in the e input under certain fault conditions to which the pp claimsrelay must respond may be a fraction of the rated In t accompanying aw 1 is a top 20 input, or of the input under other fault condi-. P View. p y broken ay d Partly in tions further limiting the available torque and section, o on 'electroresponsivc'dcvice mbodyreducing the speed of response. Moreover, beihg y invention; 2 is a Pa t sectional view cause of the relatively large disk, only a. small on the line of 3 s an ploded portion of which is in use electrically at any in- View illustrating in P p e pa ts of the de- 25 stant, the resultant disk inertia and friction load Vice shown in Figs- 1 and s- 4 a d 5 illusdelays movement in response to the torque actutrate two groups of series connected form-wound ally developed. While there maybe relays having energizing coils the device shown i s- 1 relatively high speed and sensitivity for specific and 6 illustrates a u p unit elay applications, their construction does not conveniassembly embodying eleotl'oresponsive devices of 30 ently or economically lend itself to multiple unit the p shown in i s- 1 and Fi 7 a d 8 a relays or the desired diversity in relay applicadiagrammatic outlines of the magnetic structure than whereby a given construetlon can readily of the device shown in Figs. 1 and 2 to illustrate be modified to provide different ki d of t modifications of the device for different protection, for example, over-current, power-directlontive app ic s; i 9 i a ther d rammatic a1, distance, etc.- For some applications, it is deoutline of the magnetic structure o Figs- 1 a d 2 sirable that the movable member of the relay ust another modification for a fl have a practically unlimited movement or that cnt app d a s a form oftorque va ythe developed torque be independent of movein m ns; 10 ill s r e the m netic tr merit. The induction disk relay has the advantu e w a difi a of th t q va yin 4 tage of unlimited movement, but plunger and meahsshown in a d Figs- 11 and 12 pivoted magnetic armature type relays and ring lus te modifications of t moving P o e type induction dynamometer relays do not have. devices shown in F gs 1 a d either the unlimited movement or the torque in- In t embodiment of y invention ust d dependent ofmovement features. in Figs. 1 and 2 by w y of p I Pro id 45 An object of my invention is to provide a high .a e ay torque Producing motor element w speed and high sensitivity electroresponsive decomprises a hollow magnetic stator having vice whose speed and sensitivity-factors are sevp u a y of w d y P ojecting salients II and eral times those of the induction disk relay and I2, e o membe centrally Positioned whose movable member may have an unlimited re at v to d spaced from the inner ends 50 movement and is substantially free of end play faces of the salients, a rotor of electric current and chatter, and in which torque may be made conducting material between the magnetic memindependent of movement. Another object of my ber l3 and the ends of the salients, and energizinvention is to provide an improved electroreing windings l5-and I 6 so. shaped as substantiallyas sponsive device in which the materials oi'conto fill the spaces between the salients. While I 56 have illustrated an eight salient device, it will be obvious from what follows that my invention is r not limited to this particular number although it does provide'the maximum torque for the available space consistent with low cost and diversity of application.

In order to have economy of switchboard space, I preferably arrange my device so that its vertical cross-section is rectangular. For economy of material and maximum coil space so as to obtain a high ratio of copper to iron, which is particularly important in relays having potential windings, 1E preferably make the stator iii of laminations in the form of a hollow square. Tl'iis provides the maximum usable cores window area; and hence coil volume per unit of thickness for a given space occupied by the relay. Also for economy of construction and assembly and the greater safety in coil life, resulting from the use of form- Wound coils since in random-wound coils a turn lelepipedal shape may be used in order substantially completely to" fill the space between the salients. Thus, the coils, i5 may be slipped on the salients H and the coils !6 on the detached salients 92, which are then set in the stator recesses and secured by any suitable'means, such as pins ll driven into 'holes'formed by opposed recesses 58 in the salients at adjacent corners thereof. It will be obvious to those skilled in the art that the pyramidal coils may be placed on the diagonal salients and the parallelepipedal coils on the side salients but the space economy would not be so good unless the stator is otherwise than square.

In order to have a self-supporting unit assembly for the parts just described without any necessity for acase or housing and with the required heat dissipating properties for such a compact iron and 'copper assembly, I provide suitable end frames l9 and 20. While these may be of any suitable material, aluminum or an aluminum alloy maybe used where high heat conductivity is desired. Such materials of course provide higher heat conductivity than the stator I0 and the wind ings l5 and I6. The bottom frame l9 includes suitable supporting means for the central magnetic member l3. As shown, this supp ing means is a spider 2! in a central hole 22 of which is set and secured by suitable means, such as a nut 23, a hub 24.015 nonmagnetic material on which the central magnetic member 53 is mounted. The

,hub 24 has a central hole for a. shaft, to which .the rotor hub is securedby suitable means,

such as a set screw 21. The lower'end of the hub 24 may be threaded interiorly to receive a jewelled step bearing 28 for the shaft 25, as shown in Fi 6.

For assembly purposes, the corners of the end frames 19 and 20 and'the stator Ill may have registering holes to receive hollow rivets 29 through which bolts 30 may be passedto fasten two or more units together, as shownin Fig. 6.

ariaeee there fit cylindrical projections 33 on the lower face of the end frame til. it will be obvious that units may be thus simply assembled and yet insure the necessary precision in alinement and the desired interchangeability. It will be noted that the spaces between the arms of the spider 2| are filled by the windings 15 while the windings it fill in the spaces over the spider arms, thereby utilizing the space to the best advantages. Inasmuch as the edges of the laminations are exposed to the air and the coil spaces are exposed to the inner surface of the endirames, the necessary heat dissipation is secured. A notch 34 in the end frame 20 provides an opening through which the coil leads may, be led, preferably in an insulating shell 35. Threaded holes 36 may be provided in the end frames for mounting the relay.

Since for mounting purposes it is desirable to make the cylindrical rotor i4 and its closed end of one piece of metal so that it is in effect a. cup,

it is necessary, in order to avoid end play and vibration and the highly variable torques consequent on vibration, to so construct the rotor as to maintain conductivity balance about the central flux plane of the stator i0. While this could be done by lengthening the rotor, it would'involve more space, increase inertia, and slow the action of therelay. In order to avoid entirely some of these undesirable features and minimize others, I thicken the rim of the rotor H, as shown,

but only to an extent that it will pass through the air gaps between the salients and the central magnetic member. I have found that for highest speed action, rotors of aluminum are preferable to copper because although the conductivity of aluminum is less than copper and therefore results in a torque reduction, this reduction is less than the gain resulting from the decrease in weight. In order to avoid biased torques and torques that vary with rotation, the rotor should have uniform conductivity throughout. When copper is used I have found that, since ordinary copper may contain oxide streaks of low conductivity, it is preferable to use oxygen-free highconductivity coppen- The relay shown in Fig. 6 is polyphase power directional device embodying three of the units in various-ways, examples ofwhich are wellknown to the art. If it is desired to introduce. a torque dependent upon only one of the electrical quantitiesinvolved, for example, a voltage restraint torque, as is often useful with power directional rlays,.shadlng windings 38 may be provided in the faces of the salients which are energized by the quantity in question.

Referring now to Fig. '7 and assuming that the salients H and I 2 of the stator III are provided magnetic member I3 is secured to a movable arm 2,110,686 nected to be energized with the current I and two voltages E1' and E2 of an alternating current circuit, then the torque T1 on the rotor, notshown, will be I T1=E1I sin A-E1Ez sin B A and B being phase displacement angles depending upon circuit constants of the relays. In other words, the torque consists of the particular directional current torque E1I sin A opposed by a voltage torque EiEz sin B. Thus, there results a single phase power directional relay with voltage restraint.

Fig. 8 further illustrates-the diversity of elec-- troresponsive devices embodying my invention. If it be assumed that the salients II and I2 are provided with energizing windings producing at any instantfluxes of the polarities indicated and connected to be energized in accordance with two currents I1 and I2 derived from an alternating current circuit and that the diagonal salients I2 are provided with short-circuited windings or lag rings 40, then the torque T2 on the rotor (not shown) will be beingthe phase angle lead of I1 relatively to I2 and the phase angle which the flux in salients I2 lags the current 12 in the windings on these salients by reason of the lag rings 40. This arrangement provides a single phase directional ground relay.

The modification of my invention shown in Fig. 9 illustrates a simple over-current relay with a variable pickup feature. In this case, it will be. assumed that the energizing windings 4|,

43 whereby theposition of the member I3 can be changed so'that the rings 42 encircle less and less of the flux in the horizontal salients and more and more in the vertical salients. In-this way, the torque on the rotor, not shown, can be varied gradually to zero and its direction reversed if desired. Thus, if the arm 43 moves over a suitably graduated scale 44, this can be used to control the, pick-up torque of the relay.

The relative pitches of the shading ring and salient is a measure of the range of adjustment. Thus, in Fig. 9, the pitch is large but 'for a micrometer adjustment the pitch can be small, as shown in Fig. 10, in which the pitch of the ring 45 relatively to the salient is small.

Instead of having the central magnetic member I3 stationary, I- may make it rotatable and combine with it the function of the electric current conducting rotor by applying to the exposed faces of the magnetic member I3, as indicated in Fig. 11, a copper coating 46 either by plating or spraying. For rotatable movement, the member I3 may be provided with a suitable nonmagnetic hub 4'1, as shown. Instead of plating the top and bottom faces, copper rings 48 may-be In order to secure this torque and projoining the two rings 48. The member I3-may belaminated. Constructions such as the modification shown in Figs. 11 and 12 provide higher torque than does the hollow cylindrical copper rotor because it is possible to work within practical limitations with smaller total air gaps between the salients and the central core I3, but because of the greater inertia of the rotating parts, the speed will not be as great as with the hollow cylindrical or cup rotor. While other well known rotor constructions such as the squirrel cage and hysteresis types may be used, their greater inertia reduces speed and sensitivity.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electroresponsive device comprising a magnetic stator in the form of a hollow square, said stator. having a plurality of inwardly projecting salients, alternate salients being integral with the stator and the other salients insertable in the stator, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor of electric current conducting material between said centralmagnetic member and the inner ends of said salients and form-wound coils for said salients so shaped as substantially to fill the spaces between the salients.

2. An electroresponsive device comprising a magnetic stator in the form of a hollow square, said stator having a plurality of'inwardly projecting salients, alternate salients being integral with the stator and the other salients insertable in the stator, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor of electric current conducting material rotatably mounted for movement in the gaps between said central magnetic member and the inner ends of the salients, and form-wound coils for said salients so shaped as substantially to fill the spaces between the salients.

3. An electroresponsive device comprising a magnetic stator in the form of a hollowsquare, an integral salient extending inwardly from each side of said stator, an inwardly extending dijagonal salient insertable in each of the inner erally parallelepipedal shape for mounting on the other group of salients.

4. An electroresponsive device comprising a magnetic stator in the form of a hollow square, an integral salient extending inwardly from the extending diagonal salient insertable in each of the inner corners of said stator, a magnetic member centrally positioned relatively to and. spaced from the inner ends of said salients, a rotor of electric current conducting .materia1 rotatably mounted for movement in the gaps between said central magnetic member and the middle of each side of said stator, an inwardly netic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor of electric current conducting material. rotatably mounted for movement in the gaps between said central magnetic member and the inner ends of the salients, and formwound coils for said salients so shaped as substantially to fill the spaces between the salients.

6. A relay motor unit comprising a hollow magnetic stator having a plurality of inwardly projecting salients, windings for energizing said salients, an end frame on each face of said stator, means for fastening together the end frames and stator of a unit, means for aligning a plurality of units including projections and openings on said end plates, a central magnetic member supported by one of said end frames and centrally positioned relatively to and spaced from I the inner ends of said salients, and a rotatably mounted cylindrical member of electric current conducting material movable in the gaps between said central magnetic member and the inner ends of said salients.

7. A relay motor unit comprising a hollow magnetic stator having a plurality of inwardly projecting salients, coils for energizing said salients, an end frame on each'face of said stator I forming with the edges of said stator an enclosure for said coils, said frames being of a material of high heat conductivity, means for fastening together the end frames and the stator of a unit, a central magnetic member supported by one of said end frames and centrally positioned relatively to and spaced from the inner ends of said salients, and a rotor of electric current conducting material between said central magnetic member and the inner ends of said salients.

8. A relay motor unit comprising a hollow magnetic stator having a. plurality of inwardly projecting salients, windings for energizing said sallents, an end frame on each face of said stator, means for securing said end frames and stator together, for the alinement and the fastening of a plurality of units, a central magnetic member supported by one-of said end frames and centrally positioned relatively to and spaced from the inner ends of said salients, a shaft extending through said central magnetic meniber and one of said end frames, a rotor of electric current conducting material mounted on said 4 means aiiacee said member relatively to and spaced from the inner ends of said salients, a shaft extending through said central magnetic member and one of said end frames, a rotor of electric current conducting material mounted on said shaft and movable in the gaps between said central magnetic member and the inner ends of said salients and a bearing for said shaft mountable in said support.

iii. an electroresponsive device comprising a hollow magnetic stator, a plurality of, salients extending inwardly from said stator, a magnetic membencentrally positioned relatively to and spaced from the inner ends of said salients, a

cylindrical rotor of electric current conducting material of substantially uniform thickness mounted for movement in the gaps between said central magnetic member and the inner ends'of the salients, one end of said rotor beingsubstantially closed and the rim of the other end being materially thickened to maintain the curher and the inner ends of the salients, and flux i shading means including a short-circuited winding mounted on said central magnetic member. .12. A relay motor unit comprising a hollow magnetic stator having a. plurality of inwardly projecting salients, windings for energizing said salients, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor of electric current conducting material rotatably mounted for movement in the gaps between said central magnetic member and the inner ends of the salients, flux shading including a short-circuited winding mounted on said central magnetic member, and means for turning said central magnetic member to vary the effect of said short-circuited winding.

' 13. A power directional electroresponsive, de-' vice comprising a magnetic stator in the form of a hollow square, an integral salient extending inwardly from each side of said stator, an inwardly extending diagonal salient insertable in each of the inner corners of said stator, a form- Woundcurrent coil having a generally pyramidal shape for mounting on one of the groups of said salients, a form-wound potential coil having a generally parallelepipedal shape for mounting on the other group of' said salients, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, and a rotor of electric current conducting material salients.

14. A power directional electroresponsive device comprising a. magnetic stator in the form of .a hollow square, anintegral salient extend- .between said member and the inner ,ends of the ing inwardly from each side of said stator, an

inwardly extending diagonal salient insertable in each of the inner corners of said statorl-sa form-wound current coil having a generally pyramidal shape for mounting on said -integralsalients, a form-wound potential coil having a generally, parallelepipedal shape for mounting-7 on said diagonal salienw, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor of electric current conducting material between said member and the inner ends of saidsalients, and means for providing a torque on said rotor dependent only on the energization of the potential windings including short-circuited windings in the end faces of the diagonal salients.

15. A relay motor unit comprising a hollow magnetic stator having a plurality of inwardly projecting salients, coils for energizing said salients, an end frame on eachiace of said stator forming with the edges of said stator an enclosure for said coils, means for fastening together the end frames and the stator of a unit, a central magnetic member supported by one of said end frames and centrally positioned relativelyto and spaced from the inner ends of said salients, and a rotor of electric current conducting material between said central magnetic member and the inner ends of said salients.

16. An electroresponsive device comprising a hollow magnetic stator, a plurality of salients extending inwardly from said stator, alternate salients being inserted in the stator, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a rotor .of electric current conducting material mounted for movement in the gaps between said central magnetic member and the inner ends of the salients, form-wound coils having a generally pyramidal shape mounted on alternate salients, and form-wound coils having a generally parallelepipedal shape for mounting on the other salients.

17. A relay assembly comprising a plurality of relay units mounted one against the other, each of said units comprising a magnetic stator havinga plurality of inwardly projecting salients, windings on said salients, an end frame for each face of said stator, means for fastening said end frames and stator together and a rotor of electric current conducting material, means for aligning'said relay units including a projection on one end frame of a unit registerable with an opening on the adjacent end frame of the next unit, a shaft carrying the rotors of said units, means for supporting said shaft so as centrally to position said rotors relatively to the inner ends of said salients including a bearing in one of said end frames, and means for securing said units together.

18. A relay unit comprising a magnetic stator having a plurality of inwardly projecting salients, certain of said salients being integral with the stator and the other salients being insertable in the stator, a magnetic member centrally positioned relatively to the inner'ends of said salients, coils for said salients so shaped as substantially to fill the spaces between the salients, and a short-circuited electric current conducting path centrally positioned relatively to the inner ends of said salients and adapted to rotate in response to the fluxes flowing between said salients and said central magnetic member when said coils are energized.

19. An electroresponsive device comprising a magnetic stator in the form of a hollow square, a salient extending inwardly from each side of said stator substantially perpendicular to said side, a salient extending diagonally inward from each comer of said stator, alternate salients of all of said salients being integral with said stator and the other salients being insertable in the stator, a magnetic member centrally positioned relatively to and spaced from the inner ends of said salients, a closed current conducting path rotatable in the gaps between said central magnetic member and the inner ends of said salients, and windings'for energizing said salients.

VICTOR E. VERRAIL. 

